Software Control

Your sketch can access the functions of the RFID Door Lock Shield using the following pins:

Digital pin 2: RX (receive) from RFID reader module.

Digital pin 3: TX (transmit) to RFID reader module.

Digital pin 8: Status LED output.

Digital pin 9: Strike plate output.

RFID Module

The RFID RX/TX pins can be accessed using the SoftwareSerial library in the Arduino IDE. The following example will allow you to connect an RFID module that communicates at 9600bps, and pass communications directly through the Arduino between the module and the serial terminal in the IDE. You can use this to test that communications with your module is working correctly.

Status LED

The Status LED connection is a simple breakout for digital pin 8. You can simply connect an LED and a resistor in series between this pin and GND to provide a basic output, or you can connect a pair of LEDs as shown below to allow either red or green to be displayed depending on the state of the output pin. With this arrangement, setting the output HIGH will cause the green LED to turn on, while setting the output LOW will cause the red LED to turn on.

Strike Plate

The strike plate can be activated by setting digital pin 9 HIGH.

Combined Example

The RFID Access Control System project in Practical Arduino includes an example sketch that stores authorised RFID tag IDs internally and then activates the strike plate when a tag with a matching ID is read. You can download the sketch source code from: